Styrene copolymer plastic composition



M, I M A Patented Sept. 7, 1943 p i UNITED STATES r 2,329,033 PATENT OFFICE 2,329,033 STYRENE COPOLYMER PLASTIC COMPOSITION Edgar C. Britton, Gerald H. Coleman, and John W. Zemba, Midland, Mich., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Michigan No Drawing. Application June 5, 1939,

Serial No. 277,442

Claims.

organic compounds containing olefinic linkages.

For example, Staudinger (U. S. Patent No. 2,089,444) discloses resinous polymers prepared by the conjoint polymerization of styrene and divinyl benzene. Voss et al. (U. S. Patent No. 2,047,398) describes similar polymers prepared from styrene and maleic acid derivatives, and in the co-pending applications of Britton et al., Serial No. 191,958, filed February 23, 1938; Serial No. 191,959, filed February 23, 1938, now U. S. Patent 2,186,359; Serial No. 191,960, filed February 23, 1938, now U. S2 Patent 2,186,360, Serial No. 199,892, filed April 4, 1938; Serial No. 213,022, filed June 10, 1938; and Serial No. 217,224, filed July 2, 1938 are described products prepared by polymerizing styrene in the presence-of certain unsaturated esters and ethers, e. g. the dicinnamate of 1.4-dioxanediol-2.3, trimethallyl' phosphate, allyl crotonate, 2-chloro-allyl furoate,

, triallyl phosphate, allyl 'ci'nnamate, diallyl phthalate, the di-crotonate of 1.4-dioxanediol-23, di- (2-chloroallyl) oxalate, the diallyl ether of 1.4- dioxanediol-2.3, allyl methacrylate, etc.

The above-described products are usually obtained as glass-like thermoplastic resins, although in some cases they may be obtained as opaque, white, friable materials, which, however, may be molded to form glass-like products. The polymers initially obtained as clear transparent resins may be soluble in the usual solvents for polystyrene, e. g. carbon tetrachloride, dioxane, methylene chloride, benzene, toluene, ethylbenzene, etc., or they may be capable only of swelling to form insoluble gels ,when contacted with such'solvents. The opaque, white, friable polymers are insoluble and non-swelling in polystyrene solvents. All such solid resinous prodnets are herein referred to as co-polymers,

although their exact chemical constitution is not definitely known. Similarly, the unsaturated compounds which may be employed in preparing such products are referred to as co-polymerizing agents and the polymerization of mixtures of styrene and such agents is referred to as "copolymerization. All of the co-polymers of styrene possess properties which render them valuable in the manufacture of inolded or shaped objects. For example, they are stable to dis coloration, have good dielectric strength, high mechanical strength and impermeability to moisture, and are resistant to attack by acids, alkalies, etc. 1

In preparing such molded or shaped products, however, difficulty is encountered in securing ing agents for the co-polymers of styrene, since they impart the desired properties to the copolymers only when used in such large proportions that the mechanical strength of the composition is greatly reduced. Certain of such plasticizing agents are further disadvantageous in that they tend to vaporize and exude to the surface of the plasticized composition with resultant loss in plasticizing action and, frequently, blushing of the finished product.

We have now found that the aromatic diethers of the glycols may be advantageously employed as plasticizing agents for the co-polymers of styrene. Compositions comprising styrene copolymers plasticized with relatively small amounts of the new agents possess adequate plasticity and'flow at molding temperatures, and at the same time they retain to a large extent the strength characteristics of the unplasticized co-polymers. In many cases, the plasticized copolymers even show improved strength characteristics because of the improved molding secured through the use of the new plasticizing agents. Moreover, the plasticized compositions are clear and transparent and show less tendency to blush co-polymers of styrene according to the invention may be represented by the general formula R--OCnHzn--0R wherein each R represents a xenyl, phenyl, halophenyl, alkyl-phenyl, cycloalkyl-phenyl, or alkoxy-phenyl group and n represents an integer reater than 1. Examples of such compounds are 1.2 diphenoxv ethane, 1.3-di-(4-xenoxy) -propane, 1.3-di(3-methyl phenoxy) -isobutane, 1.3- di(2.4.6-trichlorophenoxy)-propane, l-phenoxy- 2- (2-xenoxy) -isobutane, l.4-di(2-ethoxy-phenoxy) -butane, 1.5-di(2.4 dimethylphenoxy) -pentane, 1-(4-tertiarybutylphenoxy) -3- (5-chloro-2- xenoxy) -butane, 1.2 di(4-bromoph'enoxy) -ethane, 1.2 -"di(4 tertiaryoctylphenoxy) propane, 1.8-di(o-methylphenoxy) -octane, 1.21di (4-cyclohexylphenoxy) -ethane, 1.6-di(2 chloro 4 tertiarybutylphenoxy) -hexane, 1- (tertiarybutyl-2- xenoxy) -2-(2.4.6-trichlorophenoxy) -ethane, 1.3- di(2.4 ditertiarybutylphenoxy) butane, etc. These compounds vary in physical characteristics from high-boiling viscous liquids to crystalline solids. They are soluble in a wide variety of solvents and solvent mixtures, are stable to light and heat, and are compatible with co-polymeric styrene.

but is usually employed in an amount representing from 1 to 50 per cent by weight of the entire composition, the most effective amount depending somewhat upon the use to which the composition is to be put. For example, compositions which are to be employed in the manufacture of hard molded objects preferably contain from about 1 to about per cent by weight of the 15 preparing the new compositions comprises meplasticizing agent, whereas soft, rubber-like comchanically mixing the finely divided co-polymer positions contain a somewhat greater, e. g. 30 with a plasticizing agent, with or without the to 50 per cent, proportion of the plasticizing aid of solvents, in a Banbury-type mixer or on agent. The co-polymerizing agents are usually heated compounding rolls until a homogeneous employed in amounts representing 0.1 to 15 per composition is obtained. cent by weight of the styrene, although the op- The following examples illustrate a number timum amount depends upon the particular coof ways in which the principle of the invention polymerizing agent employed and upon the has been applied but are not to be construed as properties desired in the composition. The polylimiting the same: merization is usually carried out by heating the EXAMPLE i mixture of monomeric styrene, co-polymerizing agent, and plasticizing agent at a moderately Compositions comprising the co-polymer of elevated temperature, e. g. 60-180 C. for 3-14 styrene and the di-cinnamate of 1.4-dioxanedioldays, during which time the mixture gradually 2.3 plasticized with various aromatic di-ethers polymerizes to form a resinous polymer having were prepared by polymerizing mixtures containthe plasticizing agent homogeneously dispersed ing 500 parts by weight of monomeric styrene, therethrough. A large amount of heat is devel- 2.5 parts of the di-cinnamate of 1.4-dioxanedioloped during the polymerization, and when oper- 2.3, and from 5 to 125 parts of the plasticizing ating on a large scale it is advantageous to proagent. The polymerization was carried out by vide heat dissipating means in order to maintain heating the mixture at 100 C. for from '7 to 14 the desired temperature. If desired, the polydays. The compositions so prepared were in most merization may be initiated at a relatively low instances clear transparent resins which were temperature, e. g. 60 C., and the temperature insoluble in alcohol and capable of being swelled gradually increased as the polymerization proto insoluble gels by benzene and similar aromatic ceeds. I hydrocarbon solvents. These products were Compositions comprising styrene co-polymers o d, a d m d into t t p s. of the type capable of being swelled rather than employing a molding temperature of 160 C'. The dissolved by solvents may be prepared by forming test specimens were then tested for mechanical the co-polymer in the absence of the plasticizing strength, hardness, heat distortion, and softening agent, i. e. by polymerizing a mixture of monopoint. The data obtained, together with commeric styrene and a co-polymerizing agent, and thereafter causing the co-polymer to swell to a of Britton and Marshall, Serial No. 209,736, filed May 24, 1938.

A third method which may be employed in parative data on the unplasticized co-polymer, are presented in Table I below:

Table I Plasticizlng agent m Tensile Hardness Impact Heat dis- Softening No. strength (Shore) strength tortion point Name cent LbsJ sq. in. In. lbs. 1 6,800 85 1.1 2 1.2-di henoxy-ethane 9.0 5, 800 78 1.0 3 1.2-di 4-tertiarybutyl-phenoxy)-ethane 9. 0 5, 000 74 1. 1 4 do 23.0 5, 000 0. 8 5 1.2-di(4-cl1loro-phenoxy) -ethane 2. 0 6, 500 82 1. 4 6 do 9.0 7,500 77 1. 3 7 1.2-d E2A-dichloro-phenoxy)-ethan 5. 5 7, 500 83 1. 3 8 1.2-di 2.4.d-trichloro-phenoxy)-ethane 2.0 5, 700 1.4 9 1.2-di(2-0111oro-4-tertiarybutyl-phenoxy)ethane 9. 0 7, 81 1. 3 10 1.2-di(2-methoxy-phenoxy)-ethane 2. 0 8, 800 1 151-93 1. 3 11 do 5.0 5,400 3 151-91 1.0 12 10.0 5,000 1 15-7-90 0. 8 l3 4. 6 600 76 1. 4 14 o 9.0 4, 800 78 1.3 15 1.3-di(4-chloro-phenoxy)-isobutane 2. 0 8, 900 84 1. 2 16 1.3-di(4-tertiarybutyl-phenoxy)-isobutane l. 0 6, 400 85 1. 1 t 17 .-do 5.0 7, 400 75 1. 1 l8 10. 0 6, 600 83 1. 0 l9 1 2di(2-xenoxy)-ethan 9. 0 7, 700 82 1. 2 20 o 23. 0 4, 300 76 1.1 21 l.2-di(4-xenoxy)-ethane l. 0 5, 100 80 l. 3 22 0 2.5 4,900 77 1.2 23 do 10.0 3, 200 76 0. 8 24 1.3-di(2-xenoxy)-isobutane 2. 5 7, 900 83 0. 9 25 do 6. 0 7, 600 86 1. 1 26 do 10. 0 6, 800 76 0. 6

1 Average value. I Rockwell hardness.

EXAMPLE 2 The following Table II presents data illustrating the eifect of several of our new plasticizing agents on the physical properties of the co-polymer of styrene and trimethallyl phosphate. In each case a mixture containing 500 parts by weight ofmonomeric styrene, 20 parts of trimethallyl phosphate, and from 10 to 50 parts of the plasticizing agent was polymerized by heating at 100 C. for 14 days, after which time the polymerized mass was ground, dried, and molded at 160 C. to form test specimens, and the properties of the latter were determined as in Example l. 4

Table II EXAMPLE 5 A mixture of 200 parts by weight of monomeric styrene and 1.0 part of the di-cinnamate of 1.4- dioxanediol-2.3 was polymerized by heating at 100 C. for 5 days. The resinous polymer obtained was insoluble in ethanol and acetone but was capable of being swelled to an insoluble gel in benzene and similar aromatic hydrocarbon solvents. Approximately 20 parts of this copolymer were added in finely divided form to 250 parts of a 4 per cent benzene solution of 1.2 di(2-xenoxy)-ethane. The mixture was allowed to stand for several hours whereby the copolymer swelled to a firm gel, after which time Plasticizing agent Run Tensile Hardness Impact Heat dis- Softening No. T Per streng (Shore) strength tortion point A ame cent LbsJ 294. in. In. lbs. C. l 5, 200 79 1. 1 67 108 2 1.2-di(4-ch1oro-phenoxy)-ethane 0 7, 400 77 l. 4 68 118 3 o .0 6,500 73 0.9 60 104 4 1.2-di(2.4.6-trichl0ro-phenoxy) ethane. 0 6, 300 76 1. 3 72 108 5 do 9.0 5,900 81 1.2 62 99 6 1.2-di(2-chloro4-tertiarybutyl-phenoxy)-ethane 2. 0 5, 200 80 0. 8 63 117 7 do 9.0 5,100 77 0.8 63 116 8 l.2-di(2-xenoxy)-ethane 9.0 6, 300 78 1. 2 55 9 1.3-di(2-xenoxy)-isobutane 2. 0 6, 000 84 0. 9 70 117 EXAMPLE 3 Table III Per cent plasticizing agent 0.0 2.5 10.0

Molding temperature. .C.- 245-250 220-225 185-195 Molding pressure "tons" 11 8 8 Time for 1.0 flow at 135 C secs... 138 88 42 ,Time for 1.35" flow at 135 G.. do. 242 122 47 Bubbles in molded product Many Few None Impact strength of molded product in. lbs. 0.96 0. 84 0. 83 Tensile strength of molded product in. lbs.- 8,500 9, 500 8, 500

EXAMPLE 4 A mixture of 500 parts by weight of monomeric styrene, parts of diallyl maleate, parts of 1.3-diphenoxy-isobutane, and 2.5 parts of the opaque, white co-polymer obtained by polymerizing a mixture of styrene and diallyl maleate at 80 C. was polymerized by heating at 80 C. for 336 hours. The product obtained consisted of about equal parts of the glass-like, swelling type and the opaque, white, non-swelling type of copolymer. The latter material was separated, washed with acetone, ground and dried, and molded into a test specimen. It had a tensile strength of about 6400 lbs/sq. in., and a Shore hardness of about 80.

the benzene was evaporated off and the mixture was dried under vacuum. The co-polymer was obtained as a resinous mass having the plasticizing agent uniformly incorporated therein.

The invention is capable of many modifications and is not limited by the examples given above. ture of styrene, a co-polymerizing agent, and one or more of the new plasticizing agents may be carried out in the presence of solvents, emulsions, polymerization catalysts, such as benzoyl peroxide or strong mineral acids, etc., to obtain a variety of useful products. If desired, various dyes, pigments, non-thermoplastic fillers, resins, etc. may be incorporated with the new products to produce decorative effects or to modify the physical properties of the molded products.

Other modes of applying the principle of our invention may be employed instead of those explained, change being made as regards the method herein disclosed or the materials employed, provided the method stated by any of the following claims be employed, or the product claimed in any of the following claims be obtained.

We therefore particularly point out and distinctly claim as our invention:

1. A composition of matter comprising a benzene swellable co-polymer of styrene and an unsaturated ester and, as a plasticizing agent therefor, an aromatic di-ether having the general wherein R. and R each represents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals, and n represents an integer greater than 1.

2. A composition of matter comprising 9. benzene swellable co-polymer of styrene and an unsaturated ester and, as a plasticizing agent there- For example, polymerization of a mixfor, an aromatic di-ether having the general formula RO-CnH2nO-R wherein R. and R each represents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals.

4. A composition of matter comprising 9. benzene swellable co-polymer of styrene and an unsaturated ester and, as a plasticizlng agent therefor, an aromatic di-ether having the general formula CH: Rt1H-c11zoR' wherein R and R each represents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals.

5. A composition of matter comprising a benzene swellable co-polymer of styrene and an unsaturated ester and, as a plasticizing agent therefor, an aromatic di-lether having the general formula CH: n-o-cr'n-tn-cm-oav wherein R. and R each represents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals.

6. A composition of matter comprising a henzene swellable co-polymer of styrene and an unsaturated ester, and, as a plasticizing agent therefor, 1.3 di(4 tertiarybutylphenoxy) -isobutane.

7. A composition of matter comprising a benzene swellable co-polymer of styrene and an unsaturated ester and, as a plasticizing agent therefor, 1.2 di(2 chloro 4 tertiarybutylphenoxy) -ethane.

8. A composition of matter comprising a henzene swellable co-polymer of styrene and the dicinnamate of l.4-dioxanedio1-2.3 and, as a plasticizing agent therefor, an aromatic di-ether having the general formula wherein R and R eachrepresents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals, and n represents an integer greater than 1.

9. A composition of matter comprising a henzene swellable co-polymer of styrene and diallyl maleate and, as a plasticizing agent therefor, an aromatic di-ether having the general formula wherein R and R each represents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals, and n represents an integer greater than 1.

10. A composition of matter comprising a benzene swellable co-polymer of styrene and trimethallyl phosphate and, as a plasticizing agent therefor, an aromatic di-ether having the general formula wherein R and R each represents a radical selected from the group consisting of the xenyl, phenyl, halo-phenyl, alkyl-phenyl, cycloalkylphenyl, and alkoxy-phenyl radicals and n represents an integer greater than 1.

EDGAR C. BRIT'ION. GERALD H. COLEMAN. JOHN W. ZElVIBA. 

